In commercial warewashers the steps followed in cleaning dishes, flatware, glasses, etc., generally include placing the wares in a rack and placing the rack in a dolly or on a conveyor. The operator usually prerinses the wares with a manually operable flexible spray nozzle. The purpose of this step is to remove the bulk of the accumulated foreign matter. The tray then travels through a prewash station where high speed jets of water are intended to remove the remaining accumulated foreign matter. Subsequently, the wares are washed in a wash zone and then prerinsed and finally rinsed and sterilized in a rinse zone. The number of zones may vary.
The nozzles commonly employed in the prewash zone today are high pressure nozzles which tend to clog and produce an atomized spray. With an atomized spray the bubbles coalesce on the surface of the wares, and interfere with the removal of the foreign matter. Where a steady jet of water is provided, even if it is sweeping across the zone, it does not provide substantially complete contact with the wares such as a dish. This results in wares entering the wash and rinse zones not always being completely free of foreign matter.
As stated above, the primary purpose of the nozzles in the upstream portion of the prewash zone is to remove the foreign matter or scrape the wares clean. The high pressure valves do not accomplish this result.
The present invention is directed to a nozzle which provides a high velocity sheet of water which imparts a scraping action when it contacts a surface. The nozzle distributes a wide uniform sheet of water substantially free of bubbles which sheet effectively scrapes the wares it contacts. The use of the nozzle may if desired eliminate the step of manually spraying the wares prior to the prewash step in the cleaning sequence.
My invention broadly comprises a nozzle and a method of using the nozzle which includes a baffle plate having a discharge edge characterized by a plurality of projections thereon, and means to discharge a stream of water onto a least one surface of a baffle plate. The projections result in a plurality of substantially uniform discharge pressure points to increase the velocity of the water and the water is discharged as a uniform sheet. At least a portion of the contacted surface is preferably arcuate. When the stream of water is not perpendicular to the discharge edge of the baffle plate, the upstream end of the baffle plate, in reference to the direction of discharge of the water, is diminished with reference to the downstream end.
In the preferred embodiment of my invention, the nozzle comprises a baffle plate secured to a conduit. The baffle plate includes an arcuate or concave surface terminating in a discharge edge and a substantially planar portion secured along its entire edge to the conduit such that the water discharge from the conduit flows across the planar surface and then the arcuate or concave surface and is baffled or deflected uniformly across the discharge edge. The baffle plate is diminished in cross-sectional area from the upstream end of the baffle plate to the downstream end and provides a high velocity sheet of water. The nozzle is uniquely suited for use in the prewash zone of a warewasher.